The present invention relates to a new and improved scale assembly and method by which it is aligned.
A known scale assembly is disclosed in U.S. Pat. No. 4,258,810. This known scale assembly includes a platform having load transmitting assemblies at each of four corners of the platform. The load transmitting assemblies include load cells having floating pins which engage a support surface and are movable along the support surface. In order to accurately center the platform relative to an enclosing framework, the floating pins must be accurately positioned relative to the support surface. In addition, the application of sideward or horizontal loads to the platform can result in abutting engagement and the transmission of horizontal forces between side surfaces of the floating pins and side surfaces of openings in the load cells.
Although a scale constructed in the manner shown in U.S. Pat. No. 4,258,810 is satisfactory in its operation, it has been found that the application of sideward or horizontal force components to a load cell tends to be detrimental to the accuracy of the scale. In addition, the time required to install the scale is increased due to the necessity of accurately positioning the platform relative to an enclosing framework.
In an effort to minimize horizontal or sideward force components in scales, rocker pins of the type shown in U.S. Pat. Nos. 2,666,634 and 3,997,014 have been used. Other scales have used spherical balls in an effort to tend to minimize horizontal force components in a manner similar to that shown in U.S. Pat. Nos. 3,915,248 and 2,430,702.
Although the use of rocker pin or ball type force transmitting members may tend to reduce the magnitude of sideward force components to which a load cell is subjected, the force transmitting members of these known scales have been associated with stationary receivers which must be accurately located. The necessity of accurately locating the stationary receivers for the rocker pins or balls of known scale assemblies increases the difficulty of installing the scale assemblies. If the receiver is to be subsequently removed for maintenance purposes, the location of the receiver must be accurately noted so that the receiver can be put back in its original position.
If stationary receivers for the rocker pins or balls of known scales are not properly located, sideward restoring forces may be permanently locked into the scales. Thus, mislocation of the receivers can cause the balls or pins to be permanently retained in an orientation which is offset or skewed relative to their intended orientation. This results in the application of sideward force components to parts of the scale. These sideward force components are detrimental to the accuracy of the scale.